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5448206 |
Systems with increased information rates using embedded sample modulation and predistortion equalization
A system is described which achieves an increased rate of transmission by transmitting multiple symbols in one symbol time. The information in the overlapping symbols can be recovered if the symbol...
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5404378 |
Distortion compensating circuit
In a distortion compensating circuit, an initial value sufficient to provide a distortion compensating effect is previously set in a memory storage for storing distortion compensating data, whereby...
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5399998 |
Digital FM modulator
An A/D converter (1) converts analog modulation signals, such as video signals and audio signals, into digital modulation signals. A center frequency data setting circuit (6) outputs center...
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5396196 |
Quadrature modular with adaptive suppression of carrier leakage
A carrier leakage suppression circuit is disclosed which adaptively suppresses carrier leakage in a signal processing device which modulates a carrier signal with an in-phase baseband signal and a...
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5357221 |
Regulation of modulator I and Q signal phasing
Electronic apparatus generates first and second output signals having a quadrature phase relationship therebetween. A local oscillator signal with a reference phase is applied as an input to first...
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5355101 |
Quadrature modulator having circuit for correcting phase error
A quadrature modulator substantially completely compensating a phase error existing between two quadrature carriers by calculating two corrected baseband signals. One corrected baseband signal is...
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5351016 |
Adaptively self-correcting modulation system and method
A self-adjusting quadrature modulator and modulation method improve the accuracy with which digital data is impressed on an RF carrier, which is particularly useful for systems having Viterbi,...
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5332980 |
Modulation circuit having frequency sensitive power supply voltage
A modulation circuit utilized in a mobile radio communication transmitter includes an amplifier for amplifying a modulation signal and a modulator having a voltage-controlled oscillator for...
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5331293 |
Compensated digital frequency synthesizer
A digital frequency synthesizer circuit with spur compensation includes a demodulator circuit (118) for demodulating the output signal (116) of the synthesizer's accumulator (108). Demodulator...
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5289502 |
Signal processing device
A signal processing device for processing an information signal, comprises a frequency modulator arranged to receive the information signal, to frequency-modulate the received information signal...
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5168248 |
Ferri-magnetic film frequency modulator
For realizing a highly sensitive and favorably linear frequency modulator stably operating with a small-sized and readily manufactured arrangement, input and output strip electrodes are disposed in...
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5140287 |
Diode circuit flicker-noise reduction
A diode circuit in which the flicker noise generated by the diode is reduced comprises a diode (D1) connected in series with a resistor (R2) having a by-pass capacitor (C1) in parallel therewith....
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5107520 |
Adaptive predistortion circuit for a digital transmission system
An adaptive predistortion circuit for a digital transmission system includes a predistortion circuit (52 1 , 52 2 , 52 3 ) for predistorting the input data before they pass through a modulator (56)...
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5075644 |
Voltage controlled oscillator with filtered and compensated modulation
Briefly, according to the invention, a voltage controlled oscillator 200 having a control input, an information signal input, and an output is disclosed. The voltage controlled oscillator 200...
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5068874 |
Spectrally efficient digital FM modulation system
A method is described for transmitting digital data with minimum splatter and for recovering the same with a conventional frequency modulated (FM) receiver to obtain data having minimum intersymbol...
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5057796 |
Digital frequency modulation system in which high and low frequency portions are processed separately
In a frequency modulation system, a modulating signal is split into its low-frequency and high-frequency components. The low frequency component is used to modulate a carrier signal by conventional...
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5021753 |
Splatter controlled amplifier
An amplifier circuit uses a microprocessor to count occurrences of the output stage going into saturation to decide when to control input levels to the amplifier. When the output amplifier stage...
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5012208 |
Quadrature modulator having compensation for local oscillator leak
The invention relates to a quadrature modulator comprising a circuit for the compensation of a local oscillator leak signal in an output signal of the modulator, which circuit adds different...
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4994767 |
Oscillator phase-noise reduction
An output having reduced additives phase-noise in at least one defined frequency band is obained from a voltage-controlled oscillator (5) by applying a frequency-modulating signal ω m t to the...
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4985688 |
Modulation system capable of accurately compensating for nonlinearities of an amplifier connected thereto
In a modualtion system responsive to a first sampled signal (31) of a first sampling rate for supplying a modulated analog signal to an amplifier having nonlinearities to make the amplifier produce...
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4904964 |
Voltage control oscillator with modulation compensation
An improved voltage controlled oscillator (VCO) is provided whereby the control voltage is utilized for modulation compensation by a modulation compensation network (90). The modulating signal is...
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4890301 |
Arrangement for compensating errors in a quadrature modulator
An arrangement for compensating errors occurent in a quadrature modulator. Two quadrature signals (cos a(t), sin a(t)) in the baseband are generated, each of which signals is delivered to a...
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4870384 |
Frequency or phase modulation
A frequency or phase modulator, in particular a DC-coupled frequency modulation synthesizer, comprises a voltage-controlled oscillator (1) in series with a divider (2) in a phase-locked loop, and...
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4839615 |
Frequency modulating circuit for video tape recorder
A frequency modulating circuit comprising a circuit for separating a synchronizing signal from an input signal, a circuit for generating a sampling pulse in accordance with the synchronizing...
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4816782 |
Modulation sensitivity correction circuit for voltage-controlled oscillator
A modulation sensitivity correction circuit in which a phase-locked loop includes a voltage-controlled oscillator (VCO) and a phase detector. When an audio signal is applied to the VCO through an...
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4788513 |
Remanent subcarrier component suppressing device for balanced modulator
A device to be incorporated with a balanced modulator included in a sub-channel of a stereophonic modulator circuit for suppressing a subcarrier component remaining in the output signal of the...
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4755774 |
Two-port synthesizer modulation system employing an improved reference phase modulator
An improved frequency modulator apparatus for use in phase-locked loop (PLL) frequency synthesizers is disclosed which makes possible high deviation, low distortion, FM signals for a wide range of...
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4700151 |
Modulation system capable of improving a transmission system
In a modulation system responsive to a system input signal for supplying an amplifier having nonlinearities with a modulated analog signal to make the amplifier produce an amplified output signal,...
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4665372 |
Method and circuit for producing sinusoidal waves having harmonic elimination from 2π periodical square waves
A method for producing sinusoidal waves uses the steps of generating a plurality of clock signals during a 2π period, using the clock signals to control the generation of 2π periodical square...
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4636663 |
Double-balanced mixer circuit
A double-balanced RF mixer circuit comprising two differential amplifiers each of which comprises a pair of transistors the emitters of which are connected in common and the bases of which are...
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4578818 |
System for processing audio frequency information for frequency modulation
In FM transmitters, particularly land mobile FM transmitters, wherein a speech signal is pre-emphasized between 300 Hz and 3 kHz, whereafter it is filtered to provide a sharp cut-off and wherein...
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4511863 |
Combined modulation and temperature compensation circuit
A circuit arrangement for combining a temperature compensating signal from a temperature compensator with a modulation signal to provide a combined signal for driving one or more crystal...
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4503405 |
Frequency modulation using a phase modulator
A frequency modulator circuit arrangement, comprising a phase modulator (1) having a carrier signal input (2) which is fed from a carrier signal generator (18) and a modulation signal input (3)...
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4477916 |
Transmitter for angle-modulated signals
Transmitter for angle-modulated signals having an input for binary signals, a premodulation filter and a frequency modulation arrangement. In order to improve the error rate of the system of...
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4476498 |
Deviation detector for FM video recording system
The deviation of an FM signal modulated by a video signal is detected by measuring the average period of the FM signal at a measurement rate proportional to the average frequency of the FM signal....
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4383334 |
Intermodulation cancelling mixer
A mixer circuit is provided which achieves substantially reduced intermodulation distortion products as compared with conventional mixers. The present mixer circuit includes first and second mixers...
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4359779 |
FM Transmitter with frequency ramp phase and amplitude correction means
A system including a frequency ramp generator feeding a transmitting power amplifier and antenna through a phase modulator and gain-controllable, transmitter driver stage. The frequency ramp...
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4290145 |
Circuit arrangement for compensating temperature-dependent frequency variations of a crystal-controlled oscillator
A subcarrier frequency-modulated with a message signal is heterodyned with a carrier from a crystal-controlled oscillator in a mixer whose output is fed to a filter eliminating one of the resulting...
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4205241 |
Quantized modulation systems
A system for modulation of the amplitude of a d-c voltage, the amplitude of an a-c carrier, or the frequency of an a-c carrier by signal, in which the signal amplitude is continuously compared...
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4041534 |
Automatic distortion correction arrangement
The arrangement essentially comprises a corrector whose parameters are variable and controlled by a generator which during each one of periodic test time intervals, gives a random value to each of...
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3982211 |
Linearized varactor frequency modulated semi-conductor diode oscillator
The present invention relates to a frequency modulated oscillator, preferably operating within the microwave range, comprising a resonator having a reversed biased semi-conductor element, for...
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3815040 |
FEED-FORWARD, ERROR-CORRECTING SYSTEMS
In a feed-forward, error-correcting system in accordance with the present disclosure, the error signal is formed by comparing the modulation component of the signal before and after signal...
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3659041 |
FM-FM AUDIO MULTIPLEX TELEVISION BROADCASTING SYSTEM WITH REDUCTION OF UNDESIRED PHASE MODULATION COMPONENT
An FM--FM audio multiplex television broadcasting system, wherein the video carrier is phase controlled by a phase controller provided prior to the video modulation stage and including a varactor...
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3651429 |
MODULATOR COMPENSATED FOR VARYING MODULATING SIGNAL LEVEL
A phase or frequency modulator of the quadrature or Armstrong type is modified such that the amplitude of the quadrature component will be reduced in proportion to any reduction in the power of the...
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3641468 |
TIME-MODULATING APPARATUS
An apparatus with error signal precorrection for time-modulating an information signal, which upon demodulation tends to be accompanied by an unwanted component, comprises a time modulator and...
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3626331 |
AUDIO SIGNAL PROCESSOR
A modulating processing system for a phase or frequency modulated transmitter includes a differentiator and limiter for controlling the deviation of the modulated signal. The limiter includes a...
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3496473 |
AUTOMATICALLY TUNED COMMUNICATIONS SYSTEMS
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3477042 |
CONSTANT LEVEL LOADING OF F.M. MODULATOR
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3444469 |
VARIABLE-EMPHASIS COMMUNICATIONS SYSTEM OF THE FREQUENCY OR PHASEMODULATION TYPE
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3440569 |
NOISE REDUCTION IN FREQUENCY MODULATION SYSTEM
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